• Explore Scientific 3-Inch Dielectric Mirror Diagonal — High-Reflectivity Star Diagonal for Large-Aperture Refractors
  • Explore Scientific 3-Inch Dielectric Mirror Diagonal — view 2
  • Explore Scientific 3-Inch Dielectric Mirror Diagonal — view 3
  • Explore Scientific 3-Inch Dielectric Mirror Diagonal — view 4
  • Explore Scientific 3-Inch Dielectric Mirror Diagonal — view 5
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Explore Scientific

Explore Scientific 3-Inch Dielectric Mirror Diagonal — High-Reflectivity Star Diagonal for Large-Aperture Refractors

Explore Scientific 3-Inch Dielectric Mirror Diagonal — High-Reflectivity Star Diagonal for Large-Aperture Refractors

$589.99
$589.99
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The Explore Scientific 3-inch dielectric mirror star diagonal delivers bright, high-reflectivity views for large-aperture refractors. A star diagonal bends the light path 90° so you can look comfortably into a refractor or catadioptric telescope pointed high in the sky — and this large 3-inch model uses a premium dielectric coating for maximum light throughput and true color.

Dielectric coatings reflect well over 99% of light, so almost nothing is lost between your telescope and eyepiece — ideal for big refractors that demand a large, high-quality diagonal. This version features a carbon-fiber body for reduced weight.

Who it's for

For owners of large-aperture refractors who need a high-reflectivity 3-inch diagonal for bright, comfortable viewing. New to gear? See our astronomy 101 stargazing basics guide.

Key features

  • 3-inch large-format diagonal for big refractors and wide-field eyepieces.
  • Dielectric mirror coating reflecting over 99% of light for bright, true-color views.
  • Carbon-fiber body for reduced weight in the optical train.
  • 90° light path for comfortable viewing at high angles.
  • Premium build for demanding visual and imaging setups.
Specifications
Brand Explore Scientific
Model DD03-01CF
Type Dielectric star diagonal
Size 3 inch
Reflectivity Dielectric, >99% (approx.)
Body Carbon fiber

Frequently asked questions

What is a dielectric diagonal?
It uses a multi-layer dielectric coating that reflects over 99% of light, giving brighter, more color-accurate views than standard mirror coatings.

Why a 3-inch diagonal?
Large refractors and wide-field 2-inch-plus eyepieces benefit from a bigger diagonal that avoids vignetting and passes the full light cone.

Will it fit my telescope?
It's designed for large refractors with a compatible 3-inch focuser/adapter. Confirm your focuser fitting before ordering.

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Frequently Asked Questions

With a beginner telescope you can see a surprising amount — the craters and mountains on the Moon, the rings of Saturn, the moons of Jupiter, and star clusters like the Pleiades. As you get more comfortable, you can also spot nebulae and distant galaxies. Not sure which beginner telescope is right for you? Check out our Telescope Buying Guide.
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